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    The detector's output SNR as a criterion for receiver placement in MIMO DVB-T based passive coherent location

    , Article International Congress on Ultra Modern Telecommunications and Control Systems and Workshops ; 2012 , Pages 431-435 ; 21570221 (ISSN) ; 9781467320153 (ISBN) Chitgarha, M. M ; Radmard, M ; Majd, M. N ; Khalaj, B. H ; Nayebi, M. M ; Sharif University of Technology
    2012
    Abstract
    As the DVB-T (Digital Video Broadcasting-Terrestrial)'s use is outspreading, one of its interesting emerging applications is to use DVB-T stations as non-cooperative transmitters in order to detect and localize targets. An important and favorable characteristic of DVB-T for this application is its being working in a Single Frequency Network (SFN), so that multiple transmitters can be used simultaneously to detect the targets. In addition, using multiple antennas at the receiver side leads to the well known configuration known as MIMO. However, one of the obstacles, arisen in such configurations, is the receive antennas' placement in proper positions so that the detection performance is... 

    Receivers' positioning in multiple-input multiple-output digital video broadcast-terrestrial-based passive coherent location

    , Article IET Radar, Sonar and Navigation ; Volume 6, Issue 7 , 2012 , Pages 603-610 ; 17518784 (ISSN) Radmard, M ; Khalaj, B. H ; Chitgarha, M. M ; Nazari Majd, M ; Nayebi, M. M ; Sharif University of Technology
    IEEE  2012
    Abstract
    Using multiple illuminators of opportunity at the transmit side and multiple antennas at the receiver side in a passive coherent location (PCL) scheme is expected to improve the detection performance. However, in such multiple-input multiple-output (MIMO) configuration choosing the position of the receivers is an obstacle that can have significant influence on the resulting performance. In this study, the authors consider the case of digital video broadcast (DVB)-T stations as non-cooperative transmitters and introduce a procedure based on the probability of missed detection to properly place receive antennas in a MIMO digital video broadcasting (DVB)-T based PCL configuration  

    Erratum to Non-linear dynamical features of center of pressure extracted by recurrence quantification analysis in people with unilateral anterior cruciate ligament injury [Gait Posture, 31, 4, (2010), 450-455]

    , Article Gait and Posture ; Volume 32, Issue 1 , 2010 , Pages 148 ; 09666362 (ISSN) Negahban, H ; Salavati, M ; Mazaheri, M ; Sanjari, M. A ; Hadian, M. R ; Parnianpour, M ; Shrif University of Technology
    2010

    Non-linear dynamical features of center of pressure extracted by recurrence quantification analysis in people with unilateral anterior cruciate ligament injury

    , Article Gait and Posture ; Volume 31, Issue 4 , 2010 , Pages 450-455 ; 09666362 (ISSN) Negahban, H ; Salavati, M ; Mazaheri, M ; Sanjari, M. A ; Hadian, M. R ; Parnianpour, M ; Sharif University of Technology
    2010
    Abstract
    Knowledge about the non-linear dynamical pattern of postural sway may provide important insights into the adaptability (flexibility) of human postural control in response to everyday stresses imposed on the body. A commonly used non-linear tool, i.e. recurrence quantification analysis, was chosen to investigate the effect of prior anterior cruciate ligament injury on the deterministic pattern of postural sway under different conditions of postural and cognitive difficulty. In double leg stance, as postural difficulty increased from open-eyes to closed-eyes and rigid-surface to foam-surface, the centre of pressure regularity (%determinism) increased as well. In comparison to healthy... 

    Pr–Co co-doped BFO multiferroics nanomaterials for absorber applications

    , Article Ceramics International ; Volume 47, Issue 2 , 2021 , Pages 2144-2154 ; 02728842 (ISSN) Akhtar, M. N ; Yousaf, M ; Baqir, M. A ; Batoo, K. M ; Khan, M. A ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    Pr and Co co-doped BiFeO3 multiferroics of the following composition BiCoxPrxFe1-2xO3, where (x = 0.00, 0.05, 0.10, 0.15, 0.20 and 0.25) were prepared via sol-gel route. XRD, FTIR, SEM, VSM and VNA were used to evaluate the structural, phase, morphological and electromagnetic properties of Pr and Co co-doped multiferroics. All the undoped and Pr–Co co-doped multiferroics were of single rhombohedral phased whereas at higher concentration the orthorhombic structure was present. FTIR analysis exhibited the presence of orthorhombic phase. SEM images revealed that the grains of Pr and Co doped multiferroics are circular and elliptical in shape. Dielectric and electromagnetic properties were... 

    Highly regioselective ring opening of epoxides with thiols catalyzed by SbCl3 under solvent-free conditions

    , Article Phosphorus, Sulfur and Silicon and the Related Elements ; Volume 183, Issue 12 , 2008 , Pages 3018-3022 ; 10426507 (ISSN) Ghazanfari, D ; Hashemi, M. M ; Akhgar, M. R ; Foroughi, M. M ; Najafi Zadeh, F ; Sharif University of Technology
    2008
    Abstract
    The ring-opening reaction of epoxides with thiols by SbCl3 supported on Kieselguhr under solvent-free conditions, afforded high yields of β-hydroxy sulfides. Nucleophilic attack of the thiols occurs regioselectively at the less hindered side of the epoxides. Copyright © Taylor & Francis Group, LLC  

    Pr–Co co-doped BFO multiferroics nanomaterials for absorber applications

    , Article Ceramics International ; Volume 47, Issue 2 , 2021 , Pages 2144-2154 ; 02728842 (ISSN) Akhtar, M. N ; Yousaf, M ; Baqir, M. A ; Batoo, K. M ; Khan, M. A ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    Pr and Co co-doped BiFeO3 multiferroics of the following composition BiCoxPrxFe1-2xO3, where (x = 0.00, 0.05, 0.10, 0.15, 0.20 and 0.25) were prepared via sol-gel route. XRD, FTIR, SEM, VSM and VNA were used to evaluate the structural, phase, morphological and electromagnetic properties of Pr and Co co-doped multiferroics. All the undoped and Pr–Co co-doped multiferroics were of single rhombohedral phased whereas at higher concentration the orthorhombic structure was present. FTIR analysis exhibited the presence of orthorhombic phase. SEM images revealed that the grains of Pr and Co doped multiferroics are circular and elliptical in shape. Dielectric and electromagnetic properties were... 

    Radar HRRP modeling using dynamic system for radar target recognition

    , Article Radioengineering ; Vol. 23, issue. 1 , 2014 , p. 121-127 Aljorloo, A ; Hadavi, M ; Bastani, M. H ; Nayebi, M. M ; Sharif University of Technology
    2014
    Abstract
    High resolution range profile (HRRP) is being known as one of the most powerful tools for radar target recognition. The main problem with range profile for radar target recognition is its sensitivity to aspect angle. To overcome this problem, consecutive samples of HRRP were assumed to be identically independently distributed (IID) in small frames of aspect angles in most of the related works. Here, considering the physical circumstances of maneuver of an aerial target, we have proposed dynamic system which models the short dependency between consecutive samples of HRRP in segments of the whole HRRP sequence. Dynamic system (DS) is used to model the sequence of PCA (principal component... 

    A new pseudolinear solution to bearing-only tracking

    , Article IEEE National Radar Conference - Proceedings ; 2013 ; 10975659 (ISSN) ; 9781467357920 (ISBN) Hejazi, F ; Khalili, M. M ; Norouzi, Y ; Nayebi, M. M ; Sharif University of Technology
    2013
    Abstract
    The main focus of this paper is on the estimation of target motion parameters using bearing measurements. Here, based on a linearization of measurements, a recursive least squares (RLS) solution is developed. The performance of the proposed method is compared to PLE which uses the same approach in measurement linearization. Simulation results show the excellence of the proposed method over the PLE, and RLS results are in vicinity of the CRLB  

    Improvement on Q. Xie threshold proxy signature scheme against collusion attack

    , Article 2011 19th Iranian Conference on Electrical Engineering, ICEE 2011, 17 May 2011 through 19 May 2011 ; May , 2011 , Page(s): 1 - 5 ; ISSN : 21647054 ; 9789644634284 (ISBN) Atashgah, M. B ; Bayat, M ; Gardeshi, M ; Aref, M. R ; Sharif University of Technology
    2011
    Abstract
    In a (t, n) threshold proxy signature scheme, the original signer can delegate the signing power to n proxy signers such that any t or more out of n proxy signers can sign messages on behalf of the original signer, but t -1 or less of the proxy signers cannot generate a proxy signature. In this paper, we will improve the security of Xie's threshold proxy signature scheme against the new types of collusion attack was presented by Liu and Tan in 2007 We also present that our improved scheme is more efficient than Xie's scheme in terms of computational complexities  

    A nonlinear strain gradient beam formulation

    , Article International Journal of Engineering Science ; Volume 49, Issue 11 , 2011 , Pages 1256-1267 ; 00207225 (ISSN) Kahrobaiyan, M. H ; Asghari, M ; Rahaeifard, M ; Ahmadian, M. T ; Sharif University of Technology
    2011
    Abstract
    In this paper, a nonlinear size-dependent Euler-Bernoulli beam model is developed based on a strain gradient theory, capable of capturing the size effect. Considering the mid-plane stretching as the source of the nonlinearity in the beam behavior, the governing nonlinear partial differential equation of motion and the corresponding classical and non-classical boundary conditions are determined using the variational method. As an example, the free-vibration response of hinged-hinged microbeams is derived analytically using the Method of Multiple Scales. Also, the nonlinear size-dependent static bending of hinged-hinged beams is evaluated numerically. The results of the new model are compared... 

    Nonlinear size-dependent forced vibrational behavior of microbeams based on a non-classical continuum theory

    , Article JVC/Journal of Vibration and Control ; Volume 18, Issue 5 , 2012 , Pages 696-711 ; 10775463 (ISSN) Kahrobaiyan, M. H ; Asghari, M ; Hoore, M ; Ahmadian, M. T ; Sharif University of Technology
    2012
    Abstract
    In this paper, the nonlinear forced-vibration of Euler-Bernoulli beams with large deflections is investigated based on the modified couple stress theory, a non-classical theory capable of capturing size effects. The classical theory is unable to predict the size effects. In systems with the dimensions in order of microns and sub-microns the size effects are very significant. For some specific beams subjected to a concentrated force at its middle as the harmonic exciter, the size-dependent responses are investigated for primary, super-harmonic and sub-harmonic resonances. The results show that the frequency-responses of the system are highly size-dependent  

    Analytic solutions to the oscillatory behavior and primary resonance of electrostatically actuated microbridges

    , Article International Journal of Structural Stability and Dynamics ; Volume 11, Issue 6 , December , 2011 , Pages 1119-1137 ; 02194554 (ISSN) Mojahedi, M ; Zand, M. M ; Ahmadian, M. T ; Babaei, M ; Sharif University of Technology
    2011
    Abstract
    In this paper, the vibration and primary resonance of electrostatically actuated microbridges are investigated, with the effects of electrostatic actuation, axial stress, and mid-plane stretching considered. Galerkin's decomposition method is adopted to convert the governing nonlinear partial differential equation to a nonlinear ordinary differential equation. The homotopy perturbation method (a special case of homotopy analysis method) is then employed to find the analytic expressions for the natural frequencies of predeformed microbridges, by which the effects of the voltage, mid-plane stretching, axial force, and higher mode contribution on the natural frequencies are studied. The primary... 

    Stochastic security-constrained unit commitment with arma-based wind modelling considering network uncertainties

    , Article International Journal of Renewable Energy Research ; Volume 3, Issue 1 , 2013 , Pages 132-137 ; 13090127 (ISSN) Abdollahi Mansoorkhani, H ; Kia, M ; Sahebi, M. M ; Pishvaie, M ; Sharif University of Technology
    2013
    Abstract
    This paper proposes a short-term stochastic SCUC model that simultaneously schedules generating units' energy and spinning reserve in presence of wind energy. It should be noted that system uncertainties, wind farm output uncertainties and power generators and lines outages are also considered in optimization process. The proposed stochastic SCUC model is formulated as a two-stage stochastic mixed-integer programming model. Performance of the proposed formulation is proved through test systems and the results are also presented  

    Statistical modeling of consecutive range profiles for radar target recognition

    , Article Proceedings International Radar Symposium, Dresden ; Volume 2 , June , 2013 , Pages 608-613 ; 21555753 (ISSN) ; 9783954042234 (ISBN) Ajorloo, A ; Hadavi, M ; Nayebi, M. M ; Bastani, M. H ; Sharif University of Technology
    2013
    Abstract
    The high resolution range profile (HRRP) is known as the most important tool in radar target recognition. Mainly, the sensitivity to the aspect angle limits the performance of the related methods. To overcome this problem, Gaussian mixture distribution is used to model the short-term relation of consecutive HRRPs. In this work, an alternative dynamical system based method is proposed to overcome the limitations of recent methods in the field such as the independency assumption. Here, the performance of the method is tested by the data produced in an electromagnetic simulation for the radar return from an aerial maneuvering target. The results show the performance of the proposed method... 

    Investigation of the size-dependent dynamic characteristics of atomic force microscope microcantilevers based on the modified couple stress theory

    , Article International Journal of Engineering Science ; Volume 48, Issue 12 , 2010 , Pages 1985-1994 ; 00207225 (ISSN) Kahrobaiyan, M. H ; Asghari, M ; Rahaeifard, M ; Ahmadian, M. T ; Sharif University of Technology
    2010
    Abstract
    In this paper, the resonant frequency and sensitivity of atomic force microscope (AFM) microcantilevers are studied using the modified couple stress theory. The classical continuum mechanics is incapable of interpreting micro-structure-dependent size effects when the size of structures is in micron- and sub-micron scales. However, this dependency can be well treated by using non-classical continuum theories. The modified couple stress theory is a non-classic continuum theory which employs additional material parameters besides those appearing in classical continuum theory to treat the size-dependent behavior. In this work, writing differential equations of motion of AFM cantilevers together... 

    Pure sulfide Cu2ZnSnS4 layers through a one-step low-temperature PLD technique: Insight into simulation on modified back contact to overcome the barrier of MoS2

    , Article Materials Science and Engineering B: Solid-State Materials for Advanced Technology ; Volume 262 , 2020 Heidariramsheh, M ; Haghighi, M ; Dabbagh, M. M ; Mahdavi, S. M ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Targeting on the selenium free, pure sulfide kesterite compound (CZTS) allows retention of the higher band gap nontoxic absorber for a single-junction solar cell. In this work, CZTS thin films were deposited by the PLD method and the Structural/optical properties, as well as Mott–Schottky analysis, were studied at different substrate temperatures. Without undergoing the sulfurization process, the single-phase CZTS thin film is prepared at 300 ℃. In the second step, a numerical simulation is performed using the solar cell capacitance simulator to study the effect of the grading layer of MoS(Se)2 on the rear side of pure sulfide kesterite based solar cells. The device with a MoSe2 coated... 

    Proof of a conjecture on the Seidel energy of graphs

    , Article European Journal of Combinatorics ; Volume 86 , 2020 Akbari, S ; Einollahzadeh, M ; Karkhaneei, M. M ; Nematollahi, M. A ; Sharif University of Technology
    Academic Press  2020
    Abstract
    Let G be a graph with the vertex set {v1,…,vn}. The Seidel matrix of G is an [Formula presented] matrix whose diagonal entries are zero, ij-th entry is −1 if vi and vj are adjacent and otherwise is 1. The Seidel energy of G, denoted by [Formula presented], is defined to be the sum of absolute values of all eigenvalues of the Seidel matrix of G. Haemers conjectured that the Seidel energy of any graph of order n is at least [Formula presented] and, up to Seidel equivalence, the equality holds for Kn. Recently, this conjecture was proved for [Formula presented]. We establish the validity of Haemers’ Conjecture in general. © 2020 Elsevier Ltd  

    Improving the first-order structural reliability estimation by monte carlo simulation

    , Article Proceedings of the Institution of Civil Engineers: Structures and Buildings ; Volume 170, Issue 7 , 2017 , Pages 532-540 ; 09650911 (ISSN) Shayanfar, M. A ; Barkhordari, M. A ; Barkhori, M ; Barkhori, M ; Sharif University of Technology
    2017
    Abstract
    The first-order reliability method (FORM) is a well-known procedure for reliability analysis in the engineering community. It provides an efficient way to calculate the failure probability of a structure. However, it introduces an unknown error in the estimations for non-linear limit states. This paper seeks a correction for the FORM by employing Monte Carlo simulation. The proposed method combines the efficiency of FORM with the robustness of the Monte Carlo method. The merits of the proposed method are illustrated through benchmark examples. The results show the high accuracy of the proposed method and a substantial reduction in the number of samples compared with crude Monte Carlo. ©... 

    Splitting dynamics of ferrofluid droplets inside a microfluidic T-junction using a pulse-width modulated magnetic field in micro-magnetofluidics

    , Article Soft Matter ; Volume 17, Issue 5 , 2021 , Pages 1317-1329 ; 1744683X (ISSN) Bijarchi, M. A ; Dizani, M ; Honarmand, M ; Shafii, M. B ; Sharif University of Technology
    Royal Society of Chemistry  2021
    Abstract
    Micro-magnetofluidics offers a promising tool for better control over the ferrofluid droplet manipulation which has been vastly utilized in biomedical applications in recent years. In this study, the ferrofluid droplet splitting under an asymmetric Pulse-Width-Modulated (PWM) magnetic field in a T-junction is numerically investigated using a finite volume method and VOF two-phase model. By utilizing the PWM magnetic field, two novel regimes of ferrofluid droplet splitting named as Flowing through the Same Branch (FSB) and Double Splitting (DS) have been observed for the first time. In the FSB regime, the daughter droplets move out of the same microchannel outlet, and in the DS regime, the...